The war of leaks detailed in a new book by a former Pentagon official, Douglas Feith, could bolster the defense of two pro-Israel lobbyists charged with trafficking in classified information, according to defense attorneys.

In a legal brief filed Tuesday, lawyers for the two former officials of the American Israel Public Affairs Committee, Steven Rosen and Keith Weissman, cited Mr. Feith’s book, “War and Decision,” as evidence supporting their claims that the defendants thought they were acting legally when they received sensitive information from a Defense Department analyst and passed it on to reporters and Israeli diplomats.

The book by Mr. Feith, who has been subpoenaed to testify in the criminal case, contends that State Department and CIA officials regularly used leaks to gain advantage in policy debates taking place within the government.

“The evidence will show that Aipac and the defendants were among the various non-government people to whom the government decided to leak non-public, likely classified information,” the defense lawyers, Abbe Lowell and John Nassikas, wrote.

Judge Thomas Ellis III has ruled that prosecutors will have to prove that Messrs. Rosen and Weissman knew that the information they obtained was closely held national defense information and that it was improper to pass it on to others. The defense has served notice that it plans to mount a “public authority defense,” which may involve claiming that the pair’s acts were authorized by public officials or that the two men were victims of “entrapment by estoppel,” a scenario where a public official assures a defendant that certain acts are legal.

One of the pair’s sources was Lawrence Franklin, an intelligence analyst who worked in a branch of the Pentagon overseen by Mr. Feith, who faces no charges in the case. Franklin pleaded guilty in 2005 and was sentenced to more than 12 years in prison. He is now cooperating with prosecutors.

In another court filing Tuesday, prosecutors urged the judge to reject the defense’s demand to know who classified the information at issue, which reportedly relates to Iranian operations in Iraq and other subjects. “The relevant evidence is not what some government official, wholly unaware of the defendants’ activities, says now about the documents at issue,” the government lawyers wrote. “This inquiry is a fishing expedition.”

Messrs. Rosen and Weissman were set to go on trial last month, but a prosecution appeal of Judge Ellis’s rulings on classified information and other matters scuttled that date. No new trial date has been set.